A fuel gas compressor for supplying a fuel gas to a gas turbine is controlled such that a pressure of a fuel gas header is constant. For example, by combining a feedforward control which uses a preceding signal on the basis of a load of the gas turbine and a feedback control on the basis of a measured value and a target value of the pressure of the fuel gas header, a supply amount of the fuel gas discharged from the compressor is adjusted, and the pressure of the fuel gas header is controlled. As means for adjusting the supply amount of the fuel gas, an Inlet Guide Vane (IGV) provided on the upstream side of a compressor, or an Anti Surge Valve (ASV) which is provided on a bypass through which the fuel gas discharged from the compressor is recirculated to the upstream side is used. A control system of the fuel gas compressor adjusts the opening degree via the feedforward control and the feedback control, and controls the pressure of the fuel gas header.
However, in the case of a system in which a plurality of gas turbines and a plurality of fuel gas compressors are provided, when the pressure of the fuel gas header is controlled, there is a problem of how a load of each compressor is determined. For example, a method may be considered, in which each gas turbine and each compressor are associated with each other in a one-to-one correspondence, and a load corresponding to the load of the gas turbine associated with each compressor is assigned to each compressor. In addition, a method which equally assigns a load to each compressor with respect to a total load of the gas turbine may be considered (for example, PTL 1).